1. Field of the Invention
The present invention relates generally to a system for accurately metering and controlling the amount of feed distributed to feed bunks in a livestock feeding operation such as a feedlot. More particularly, the inventive system allows precise computer control of a feed distributing vehicle so that feed is uniformly distributed in bunks of various lengths serving feedlot pens of varying configurations.
2. Description of the Related
A large percentage of production beef cattle and other livestock are fed by commercial feedlot operators. These businesses often constitute independent operations which accept cattle from farmers or ranchers at a certain age and size and feed them until they reach a size at which they are ready for slaughter. In return, the farmer or rancher pays a rental fee for space and care in the feedlot pen and for the feeding costs plus operating profit of the feedlot.
In the feedlot, cattle are grouped in pens according to their feed requirements, e.g. cattle of a like age and size should be fed the same ration in the same amount. Feeding is accomplished by driving a feed truck or other feed distributing vehicle along feed "bunks" which extend continuously along one or more sides of each pen. The cattle are generally fed several times daily and it is very important for uniform growth and health that each animal receive the assigned ration each day. This not only means that the proper total amount of feed must be distributed to each pen each day, but that the feed must also be evenly distributed throughout the bunk. This is due to the fact that cattle are creatures of habit and therefore they have a strong tendency to feed from the same place in the bunk each time. Thus, each animal must have its proportion of the total bunk feed available to it within its immediate feeding area in order to maximize consumption.
Typically, commercial feedlots have distributed feed via feed trucks which are driven along each feed bunk. Each truck has a feed storage hopper mounted on it which is connected to a feed distributing chute via a hydraulically and/or manually controlled door. Often a feed transfer auger is positioned to lift feed from the hopper door opening to the distributing chute. The rate at which feed is distributed thus depends upon the ground speed of the truck, the speed of the transfer auger and the positioning of the door. The truck driver is given a listing of pen numbers and feed amounts to be distributed to each pen in his route. It is up to the driver, based upon experience and "feel", to open the chute door the requisite amount and to drive the truck the correct speed to distribute the assigned feed amount evenly throughout each bunk.
The rate of feed distribution is often displayed to the driver on a display, but the feed rate is usually derived via a plurality of load cells placed beneath the feed hopper on the truck. These load cells convert the weight of the hopper to an electrical signal which is sent to a monitoring scale. There are often four load cells, one positioned at each corner of the hopper, and the scale monitors each load cell and derives a total weight for the hopper and feed contained therein by accumulating the weight information forwarded from each load cell. When the known empty weight of the hopper is subtracted out, the weight of feed remaining is displayed to the driver.
The problems inherent in the prior art approach are numerous. Under ideal conditions, each pen would be identical in size and shape and each bunk would be identical in length. However, feedlots are seldom constructed under ideal conditions, and, furthermore, the original design conditions are subject to constant change. Topography often dictates that pens will vary in size and shape, and, therefore, the lengths of bunks will vary. The positioning of gates and other pen construction considerations often shorten the length of a bunk serving a particular pen relative to even other pens of identical construction. It is difficult or impossible for a typical feed truck driver, even if he is aware of these bunk length variations, to properly compensate for them by adjusting the feed rate and/or vehicle ground speed. This inability to properly adapt feed rate to bunk length often results in a driver dispensing the total feed amount over less than the total bunk length. Alternatively, a driver will often reach the end of the bunk without having distributed the requisite feed amount. This means that he will need to shut off the feed door, back up the truck, reopen the feed door and distribute the remainder of the bunk allotment over a small portion of the bunk. Furthermore, this requirement to back up and retrace a portion of the bunk, when repeated many times per day, greatly adds to the time and expense of feed distribution. It has been estimated by some feedlot operators that fully 50% of a driver's feeding time is spent backing up and covering bunk lengths twice. This situation also increases fuel consumption and adds to vehicle maintenance expense by causing increased wear on brakes, transmissions, tires, etc.
Another problem with prior art distribution systems is the imprecision with which feed rates and vehicle speeds are monitored. Load cells positioned beneath a hopper give a fairly accurate reading of the total feed amount in the hopper when the feed truck is not in motion. However, when the truck is in motion, particularly on the rotted and/or muddy road conditions which often occur in feedlots, the inertial effects of constant swaying and jolting, starting and stopping, and acceleration and deceleration of the truck causes the load cells to be constantly differentially loaded and unloaded. The result is that the amount of feed sensed by a connected scale can vary instantaneously by several hundred pounds. It is readily apparent that a feed rate derived from such an inaccurate weighing system will itself be subject to large inaccuracies. One approach of past distributing systems has been to provide limits to the feed rate swings sensed by load cells by providing synthesized high and low rate change limits. One example of such a system is taught in U.S. Pat. No. 4,762,252 to Hyer et al. In this patent, the synthesized rate change is maintained until the sensed feed rate returns to a normal range. Unfortunately, with rough road conditions, this can take several seconds during which the truck driver is being fed erroneous rate information.
For truck speed sensing, feedlot operators often simply use the standard track speedometer or tachometer. However, feed trucks during a bunk distribution run usually travel at speeds better measured in feet per minute, i.e. speeds which may not even register on a standard speedometer and engine speed variations which may not be accurately reflected on a tachometer. This requires a driver to establish and vary his truck speed by feel and experience. This is not only an extremely inaccurate method of speed regulation, but also requires unacceptable training times for feed truck drivers, otherwise relatively low skill and low pay positions with consequent high turnover rates. It has been estimated that a typical driver can be trained to "know" the feedlot, bunk routing etc. within a week, but that it takes upwards of three months to train a driver to obtain the feel of a vehicle to a point where he can adequately distribute feed to the various bunks on his route. Furthermore, there are a large number of different manufacturers of feed trucks, with some manufacturers making several different models. Consequently, a single feedlot often operates two or more different types of feed trucks. Often the trucks are different enough that a driver must be virtually totally retrained on each truck model. These extensive training times and costs and the inconsistent feeding during training, exact an intolerable cost from the average feedlot.
It is clear then that a need exists for a system which is capable of reliably and effectively monitoring the feed rate and feed vehicle speed for a cattle feeding operation. Such a system should provide for the input of custom feeding instructions to accommodate varying pen configurations and bunk lengths and should reliably provide for consistent control of the feed rate and vehicle speed to allow the allotted feed amount to be evenly distributed throughout each bunk. Furthermore, in addition to providing information which allows the driver to precisely control the vehicle, the system may also provide for real time correction of vehicle speed and feed rate to adjust for changing conditions.